Back-Calculated Casing Wear Factor Prediction
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Solution Overview
Problem
Current methods for estimating casing wear in well systems are inefficient, relying on laboratory-derived casing wear factors that often overestimate wear, leading to unnecessary expenses and requiring frequent physical measurements, which are costly and disruptive to operations.
Innovation Solution
A method to derive a casing wear factor based on actual field wear logs using a back-calculated process, refining the factor through iterative comparisons between estimated and actual remaining wall thickness values to improve prediction accuracy and reduce the need for physical measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If laboratory-derived casing wear factors are used for estimation, then the prediction process is simple, but the accuracy of casing wear prediction deteriorates leading to overestimation
Solution Approach 1:
The patent transforms the casing wear factor from a static laboratory-derived parameter to a dynamic field-calibrated parameter. By changing the source and calibration method of the wear factor (from lab conditions to actual field conditions through iterative back-calculation), the prediction accuracy improves while maintaining computational simplicity
Solution Approach 2:
The patent implements feedback by using actual measured casing wear data from the field to continuously refine and recalibrate the casing wear factor. This closed-loop approach where measurement results feed back into parameter adjustment resolves the contradiction by improving accuracy through iterative calibration without increasing process complexity
2Measurement precision
If frequent physical measurements of casing wall thickness are performed, then the accuracy of wear monitoring is improved, but operational disruption and costs increase
Solution Approach 1:
The patent creates a computational model that copies and simulates the physical measurement process through mathematical calculations. Instead of repeatedly performing physical measurements, the system uses a calibrated wear factor to compute estimated wear values, providing continuous monitoring data without physical intervention
Solution Approach 2:
The patent replaces the mechanical measurement system (physical caliper measurements requiring well shutdown) with a computational estimation system. By substituting physical measurement with mathematical calculation based on calibrated wear factors, the system maintains monitoring accuracy while eliminating operational disruption
3Ease of manufacture
If laboratory-derived casing wear factors are used, then the initial setup is simple, but unnecessary expenses are incurred due to overestimation and frequent measurements
Solution Approach 1:
The patent performs preliminary field calibration by collecting initial measured wear data and calculating the actual casing wear factor before full-scale operation. This preliminary action of calibrating the wear factor with real field data prevents subsequent overestimation and unnecessary expenses while maintaining ease of implementation
Solution Approach 2:
The system uses its own operational data (actual wear measurements from the field) to self-calibrate and refine the wear factor. This self-service approach allows the system to automatically adjust to actual conditions, eliminating the need for conservative overestimation and reducing operational expenses
Data Source
AI summary
A method for determining casing wear of casing in a wellbore, a computer program product for determining a back-calculated casing wear factor (CWF) value for casing in a wellbore, and a well site controller are provided herein. In one embodiment, the well site controller includes: (1) an interface configured to receive actual remaining wall thickness (RWT) values that correspond to a set of casing depth values of a wellbore and (2) a processor configured to determine a back-calculated casing wear factor (CWF) value for the wellbore based on a comparison between the actual RWT value and an estimated RWT value, for the set of casing depth values, where the estimated RWT value is calculated using an estimated CWF value as input.